1. Field of the Invention
The present invention is generally in the field of electronics. More particularly, the invention is in the field of semiconductor structures.
2. Background Art
Programmable fuses, such as programmable fuses that are electrically blowable, can be utilized in integrated circuit (IC) chips to perform various functions such as, for example, providing redundancy in semiconductor memory, such as static random access memory (SRAM), adjusting the frequency of semiconductor LC oscillators, and selecting an I/O interface for a particular application. A conventional programmable fuse, such as a conventional polysilicon (poly) gate fuse, requires a high voltage to program the fuse. As device dimensions, such as gate oxide thickness, are scaled down in size in advanced technologies, the high programming voltage required by conventional poly gate fuses, for example, can cause an increase in gate oxide leakage current, which can undesirably affect the operation of the fuses.
A conventional poly gate fuse can include a poly gate situated over a gate oxide layer, which can be formed on a substrate. The conventional poly gate fuse can be programmed by applying a sufficiently high voltage, such as a voltage of between 6.0 and 7.0 volts, to the poly gate so as to cause the gate oxide layer to breakdown, thereby causing the poly gate to short to the substrate. However, as gate oxide is scaled down in thickness, the high voltage required to program the poly gate fuse can cause increased leakage in the gate oxide layer, which can undesirably increase the number of programming cycles required to permanently break down the gate oxide layer. Also, high programming voltage can cause an undesirable increase in leakage current in circuits associated with the conventional poly gate fuse, such as charge pumps that provide the programming voltage.